Abstract
The effect of strain in 1,2-elimination reactions that form methylenecyclopropanes has been evaluated for a series of leaving groups. The worse the leaving group, the greater is the inhibitory effect of strain build-up, which reaches 50% of the excess enthalpy differential for the poorest leaving group studied.
In nucleophilic addition to an electrophilic methylenecyclopropane, comparison of strained and unstrained systems shows that about 60% of the excess enthalpy differential promotes the reactivity of the strained system.
Acknowledgments
Dedicated to Professor Marian Mikołajczyk, CBMiM PAN in Łódź, Poland, on the occasion of his 70th birthday.
Notes
a Of 1-Ethoxy-1-phenylsulfonylmethylcyclopropane 11, R═OEt.